<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>

    if (navigator.geolocation) {
        navigator.geolocation.getCurrentPosition(locationSuccess, locationError,{
            // 指示浏览器获取高精度的位置，默认为false
            enableHighAcuracy: true,
            // 指定获取地理位置的超时时间，默认不限时，单位为毫秒
            timeout: 5000,
            // 最长有效期，在重复获取地理位置时，此参数指定多久再次获取位置。
            maximumAge: 3000
        });
    }else{
        alert("Your browser does not support Geolocation!");
    }

    function locationError(error){
        switch(error.code) {
            case error.TIMEOUT:
                alert("A timeout occured! Please try again!");
                break;
            case error.POSITION_UNAVAILABLE:
                alert('We can\'t detect your location. Sorry!');
                break;
            case error.PERMISSION_DENIED:
                alert('Please allow geolocation access for this to work.');
                break;
            case error.UNKNOWN_ERROR:
                alert('An unknown error occured!');
                break;
        }
    }

    function locationSuccess(position){
        var coords = position.coords;
        alert(coords.longitude);
    }
</script>
</body>
</html>